How Do You Use a Prottractor Again
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A protractor is a handy tool used to measure and draw angles. Generally, semi-round in shape, protractors are as well available in total-circle, 360-degree versions. If one look at the object has you completely confused, never fearfulness; learning to use the tool is elementary. Past understanding how the parts of a protractor are used together and following a few piece of cake steps, you will be an angle skilful in no time.
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1
Gauge the measure of your bending. Angles can be classified in three ways: acute, obtuse, and correct. Acute angles are narrow (less than ninety degrees), obtuse angles are wide (greater than 90 degrees), and right angles are exactly 90 degrees (ii lines perpendicular to each other).[1] You tin easily identify by eye, the category of angle y'all are trying to measure. Doing this stride first helps you identify which scale to utilise on the protractor.
- At a glance, we can tell this angle is acute because it is less than xc degrees.
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2
Place the origin over the center bespeak, or vertex, of the angle you want to mensurate. [2] The small hole in the middle of the base of the protractor is the origin. Align the vertex of the bending with the center of the cross in the origin.
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Rotate the protractor to align ane leg of the angle with the baseline. Maintain the vertex of the bending in the origin and gently rotate the protractor so that one of the legs of the bending falls on the baseline of the protractor.[3]
- The baseline is parallel to the edge, but is not the flat edge of the protractor. Information technology is aligned with the center of the origin and the line projects to the offset of the scale on either side.
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4
Follow the opposite leg of the bending upwards to the measurements on the protractor's arc. If the line does not pass through the protractor'southward arc, extend the angle's line until it does. Alternatively, yous tin can align the edge of a piece of newspaper with the angle's leg to laissez passer across the edge of the protractor, continuing the line of the angle. The number the line passes through is the bending'southward measurement in degrees.
- In the above example, the angle measure is thirty degrees. We know to use the smaller scale considering we determined that our angle was less than ninety degrees in the first step. If the angle was obtuse, we would use the calibration that indicated an bending larger than ninety degrees.
- Initially, the measurement scale may seem confusing. Most protractors have 2 opposing ruler grids, 1 on the inner side of the arc and one on the outer. This makes the tool handy for measuring angles originating from either direction.
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1
Draw a straight line. The line is your reference line and the first leg of your bending. It will be used to determine the position at which you draw the 2nd leg of the bending. It's generally easiest to draw the direct line in a horizontal position on the paper.
- You lot tin apply the apartment border of your protractor to describe this line.
- The length of the line doesn't matter.
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two
Place the origin of the protractor at one stop of the line. This point will be your angle's vertex. Mark the newspaper where the vertex is placed.[4]
- You don't have to place the point at the edge of the line. It tin exist placed anywhere on the line, just is easier just to apply the finish of the line.
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3
Observe the degree of the angle you lot wish to draw on the protractor's advisable scale. Marshal your reference line with the protractor'due south baseline and mark the paper at the degree of measurement. If y'all are drawing an acute angle (less than 90 degrees), utilize the scale with the smaller numbers. For birdbrained angles (greater than 90 degrees), use the calibration with larger numbers.
- Recollect, the baseline is parallel to the edge, but is not the flat edge of the protractor. Information technology is aligned with the heart of the origin and the line projects to the start of the scale on either side.
- In the in a higher place example, the angle is forty degrees.
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4
Draw the second leg to complete the angle. Using a ruler, the flat edge of your protractor or another straight edge, connect the vertex with the marked degree, drawing the 2d leg. This second leg completes your angle. To verify you've fatigued the angle accurately, utilize the protractor to measure it.
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Add New Question
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Question
When do I utilize the outer scale of the protractor?
The inner scale is for angles that open to the right and the outer scale of the protractor is used to measure angles that open to the left .
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Question
How can I tell whether I need to use a larger or smaller protractor?
The angle on a protractor will ever be the aforementioned.You may find information technology easier to have a modest protractor when only drawing a small line from the bending you lot are measuring.
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Question
Why does the protractor have readings on both sides?
So y'all can read angles form different directions. Information technology's kind of similar opposite/mirror images.
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Question
How do I observe if the angle is negative or positive?
All angles -- as typically expressed in the context of geometry -- are positive. Any angle yous measure with a protractor may exist thought of every bit positive.
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Question
Why is information technology important to utilize a protractor?
If yous want to precisely find the degrees in an bending, the protractor is probably the all-time tool.
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Question
Is an birdbrained or acute angle ameliorate?
There'southward no better angle, they are simply measurements.
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Question
Does it thing what company the protractor is made by?
No need to worry what visitor the protract is fabricated by. They all give you accurate measurements of angles, regardless of the company.
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Question
Should I start measuring from the left or from the correct?
Yous can measure from either end.
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Question
Is a right angle 90 degrees?
Yep. A right angle is i that measures 90 degrees. That is common knowledge for any educatee of math to memorize.
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Question
How practise I decide which scale to use when I apply a protractor to draw or measure an bending?
The scales are identical. One increases from the left side; the other increases from the right side.
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Things You'll Need
- pencil/pen
- paper
- protractor
- ruler (optional)
References
About This Commodity
Article Summary X
Yous can use a protractor to mensurate and draw angles. To measure angles with a protractor, first identify the center point forth the bottom border of the protractor over the vertex of the angle you're measuring. Line upwardly the bottom edge of the protractor with ane leg of the angle. Follow the other leg of the angle up to the protractor's arc to see what number information technology intersects with and find the degree of the angle. If the angle is facing to the right, use the lesser row of numbers on the protractor. If the angle is facing left, employ the elevation row of numbers. To draw an angle with a protractor, kickoff place the center indicate along the lesser edge of the protractor where you lot want the vertex of the angle to be. Depict a small dot in the hole on the protractor to mark the vertex. Then, line the lesser border of the protractor upwardly with the vertex and draw a directly line along it. Now, observe the hash mark on the protractor that corresponds with the angle you desire to describe, and draw a small dot outside of it. Rotate the protractor and line the bottom border upwardly between the vertex and the small dot. Finally, use the lesser edge of the protractor as a straight border to describe a line between the two points. Keep reading the commodity if you desire to larn how to draw angles with your protractor!
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